Korbin Sims will head to England to play in Super League, after being released from his contract by St George Illawarra.
The move was announced on Friday morning, ending a two-year stint with the Dragons where he played 21 games.
Three positions remain in the club's top 30, as new coach Anthony Griffin begins to restructure his squad following the departure of Paul McGregor.
The Dragons have re-signed prop Kaide Ellis on a one-year deal.
"I'd like to thank Korbin for his contribution at the Red V and wish him all the best in his future endeavours," Dragons football manager Ben Haran said in a statement.
"Kaide arrived at the Dragons in recent months with high credentials and he certainly proved a positive addition to our team in the back end of last season.
"The player market moves fast in rugby league and a lot of things can happen in a short amount of time.
"With three spots remaining on our roster, we'll be working diligently over the coming months to ensure the players who do come to the Dragons are the right fit for our club."